Forchlorfenuron treatment improves fruit weight and flavor quality of the red-fleshed kiwifruit ‘Donghong’

Abstract Objectives Actinidia chinensis var. chinensis ‘Donghong’ is a major red-fleshed kiwifruit cultivar widely planted in China. Its naturally small fruit size necessitates the application of forchlorfenuron (CPPU), a cytokinin-like growth regulator, to increase fruit weight and yield in commercial production. However, the effects of CPPU application on ‘Donghong’ fruit maturity, postharvest softening, storage disorder, and sensory and flavor quality of ripe fruit remain inadequately understood. Materials and methods Fruit samples were treated with CPPU immersion at different concentrations (0, 10, and 20 μL/L) and application times (14, 20, and 26 d after petal fall (DAPF)), and their impacts on fruit maturity near and at commercial harvest, fruit softening, storage disorder, and sensory and flavor quality were investigated. Results All CPPU treatments significantly increased fruit weight by 57.8%–98.1%, depending on the concentration and time. CPPU application advanced fruit maturity, but had a slight adverse impact on fruit shape and dry matter when the fruit were commercially harvested. Fruit softening during cold storage was more strongly associated with harvest time, which was in turn regulated by CPPU treatment. Chilling injury was more prevalent in the early-harvest fruit, but the CPPU-treated fruit exhibited lower incidence of skin spot disorders. The sensory and flavor quality of ripe fruit were strongly improved by CPPU application, mainly through decreasing perceived sourness and titratable acidity content, but there were no significant differences among the CPPU treatments. Conclusions Considering the overall storage performance, a medium concentration (10 μL/L) of CPPU should be applied to ‘Donghong’ fruit at early stages (14–20 DAPF).